The present invention relates to an azoamide compound excellent in the solubility in various solvents and useful as a polymerization initiator and the like; and to a novel macroazo compound having in one molecule two types of azo groups different from each other in the decomposition activity.
In the recent years, polymeric compounds have progressed from general purpose polymer to functional polymer, and block polymers which can be expected to manifest various functions effectively are being watched with interest. In such a state of things, an attempt to prepare a block polymer by the use of an azo compound was proposed, and a straight chain high-polymeric azo compound having a plurality of azo groups on the main chain obtained through an alternating polycondensation of an azo compound and a bifunctional compound was reported in JP-A-64-62318. However, the polymeric azo compounds reported in the above-mentioned patent gazette were made of a single azo compound, and therefore the azo groups existing on the main chain are all identical with each other in the decomposition activity. Thus, in order to leave a desired portion of the azo groups undecomposed in the first step of polymerization and to use the undecomposed portion of azo group in the second step of polymerization, it was necessary to control the temperature and time of polymerization strictly in the first step of polymerization. Further, the starting azo compound was inferior in solubility, so that no sufficient function as a polymerization initiator could be exhibited.
With the aim of solving these problems, an azo compound obtained by subjecting two kinds of azo compounds different in decomposition activity to a condensation reaction was reported (U.S. Pat. Nos. 3,763,129, No. 3,868,359, No. 3,649,614, No. 3,956,269, etc.). Such azo compounds, however, had at most 2 or 3 azo groups in one molecule, and therefore when such an azo compound was used as a polymerization initiator, the following difficulties arose: (1) a polymer of high molecular weight was difficult to obtain, (2) when the number of azo groups was 2, only an AB type polymer could be obtained, while when the number of azo group was 3, only an ABA type polymer could be obtained (A is a segment derived from a monomer A and B is a segment derived from a monomer B, hereinafter the same), (3) a number of radicals derived from the initiator, not participating in the polymerization, were formed, and (4) the kind of monomer which can be polymerized by this method was limited, because the azo compound was low in solubility in itself.